Field of the Invention
The present invention relates to a light-emitting device.
Discussion of the Background
Lighting devices using a plurality of light-emitting diode (LED) elements are known as replacements for light bulbs, fluorescent lamps, and other optical sources for illuminating purposes. LED elements consume lower power than light bulbs, fluorescent lamps, and other optical sources do. However, since LED elements are point sources, they provide narrower ranges of directivity. This necessitates some tens to hundreds of LED elements to be used in the lighting devices, and these LEDs need sealing by light-transmitting resin to form a light-emitting surface of approximately uniform brightness.
Japanese Unexamined Patent Application Publication No. 2011-009298 discloses a light-emitting-diode optical source device that includes a thermally conductive base, an insulation plate, and a plurality of LED elements. The insulation plate is fixed to a surface of the base and has a conduction pattern and a through hole that are formed on a surface of the insulation plate. The plurality of LED elements are mounted in a mounting area that is on the surface of the base and that is exposed by the through hole.
Japanese Unexamined Patent Application Publication No. 2002-208740 discloses a light-emitting diode that includes an LED element and a particulate phosphor. The LED element is disposed on a support. The phosphor is disposed over the LED element and the support. The phosphor absorbs at least part of light emitted from the LED element, changes the wavelength of the absorbed light, and emits the light. The light-emitting diode has a first coating portion and a second coating portion. The first coating portion includes a part of the phosphor that is disposed on the LED element. The second coating portion includes a part of the phosphor that is disposed on the support and that is not disposed on the LED element. The first coating portion and the second coating portion have approximately the same thicknesses.